Brucey, FYI,
BAS Hybrid - Wikipedia, the free encyclopedia
refers to a "high tension belt", perhaps not your standard belt.
indicates there is no electric only mode,
and they changed the final drive ratio and added auto-stop so you can't really tell what contributions the motor and batteries made to the mpg changes.
If I were adding a lot of weight to support an electric motor, I wouldn't want to then handicap the electric motor by making it constantly spin the gas motor. It can't even move the car by itself in the BAS (read: easy to implement, but crap) system.
I have to think hooking it up to a wheel, even if geared for some target max mph, would allow a much greater energy contribution from the batteries with the right management strategy. You have to carry all those batteries up a lot of hills in wv.